Suppose that some country, or the world, could be in either of two states. In state A, there would be a large population, who would all have a high quality of life. In B, there would be twice as many people, and these people would all be worse off than everyone would be in A. Most of us, I claimed, would believe that

B would be worse than A.

But there is a problem raised by another possible state of the world, which I called A+. This state differs from A merely by containing an extra group of people, whose lives would be well worth living, though they would be worse off than everyone would be in A. Most of us, I claimed, would believe that

A+ would not be worse than A.

Given certain further assumptions, we would believe that

B would be better than A+.

These three beliefs are all, I claimed, plausible; but they cannot all be true. B cannot be worse than A if it is better than something which is not worse than A. I also claimed that, of these beliefs, the hardest to deny are (2) and (3). So we seem forced to abandon (1). We seem forced to conclude that, compared with the existence of a large population whose lives were well worth living, it would be better if there were twice as many people, who would all be worse off. Since that is hard to believe, I called this the Mere Addition Paradox1.

In his excellent article, David Boonin-Vail describes a corresponding Oughtness Paradox. According to him, most us would believe that

choosing to produce B would be morally worse than choosing to produce A;

but we would also believe that

choosing to produce A+ would not be worse than choosing to produce A,

and that

choosing to produce B would be better than choosing to produce A+.

These three beliefs also seem to be inconsistent. And, since it seems hardest to deny (5) and (6), we seem forced to abandon (4).

This paradox, Boonin-Vail argues, can be solved. When we give a more accurate description of these beliefs, we can show them not to be inconsistent. By solving this paradox, Boonin-Vail then claims, we can deprive the Mere Addition Paradox of its moral force2. If Boonin-Vail is right in his description of our beliefs, his paradox can, I agree, be solved. But mine, I shall claim, retains its force.

Pages 280 and 307 above. Boonin-Vail discusses, not (5), but the claim that choosing to produce A+ would be better than choosing to produce A. I have ignored this complication, since it does not affect what I have to say.